WO2021210025A1

WO2021210025A1 - Compositions and methods for coatings, antimicrobial textiles, sanitization and disinfection

Info

Publication number: WO2021210025A1
Application number: PCT/IN2021/050382
Authority: WO
Inventors: Rinti Banerjee; Kiran Jadhav; Kapil PUNJABI; Roshan KESHARI; Eshant BHATIA
Original assignee: Indian Institute Of Technology Bombay
Priority date: 2020-04-17
Filing date: 2021-04-17
Publication date: 2021-10-21

Abstract

The present invention provides compositions and methods for providing a wash-resistant antimicrobial coating to textiles and for sanitization and disinfection. In general, the present invention provides a composite composition for sanitizing and disinfecting various surfaces or fabrics/textiles. The composition of the present invention may be used as a coating material for textiles and as an aerosol disinfectant for various surfaces. Particularly, the composition of the present invention comprises a biopolymeric base which encapsulates essential oil and fatty acid constituents making it an effective antiviral, antibacterial, antifungal and antimicrobial material. The present invention also relates to methods for preparation of said composition, aerosol disinfection and coated fabrics or textiles. The present invention further provides method for treating textiles or surfaces with said composition for sanitization and disinfection.

Description

COMPOSITIONS AND METHODS FOR COATINGS, ANTIMICROBIAL TEXTILES, SANITIZATION AND DISINFECTION

FIELD OF THE INVENTION

The present invention relates to compositions and methods for coatings, antimicrobial textiles, sanitization and disinfection of various surfaces. In general, the present invention relates to a composite composition for sanitizing and disinfecting various surfaces or fabrics/textiles. The composition of the present invention may be used as a coating material for textiles and as an aerosol disinfectant for various surfaces. Particularly, the composition of the present invention comprises a biopolymeric base which encapsulates essential oil and fatty acid constituents making it an effective antiviral, antibacterial, antifungal and antimicrobial material. The present invention also relates to methods for preparation of said composition, aerosol disinfection and coated fabrics or textiles. The present invention further relates to method for treating textiles or surfaces with said composition for sanitization and disinfection.

BACKGROUND OF THE INVENTION

Disinfecting and sanitizing compositions which have the ability to reduce or even eliminate micro-organisms existing on a surface/textile have been described in the art. However, it has been found that such compositions generally comprise disinfecting components which do not provide sustained disinfection over a prolonged period of time.

It is therefore an object of the present invention to provide effective disinfection/sanitization using ingredients which provide effective and sustainable disinfection without the use of harmful chemical agents.

The present invention provides a composition comprising antimicrobial components that in combination provide sustainable and prolonged disinfection as well as sanitization. The composition of the present invention in fact provides excellent disinfection/sanitization over a range of bacterial, fungal and viral strains.

The compositions of the present invention can be used for treating various surfaces as well as coating textiles or fabrics. EP2618926B 1 discloses a new delivery system for pharmaceutical, cosmetic and/or alimentary active ingredients based on polymeric nano-capsules which contain micro-emulsions of water in oil (w/o) and which comprise at least one hydrophilic active ingredient dissolved in the aqueous phase. This can be used to treat textile materials. The active ingredient can be and antiviral drug or compound. The patent only describes a polymeric material to encapsulate micro-emulsion with an active ingredient. It does not include essential oil and bioactive components within a biopolymer.

US20100086617A1 discloses an antiviral fiber which is made by cross-linking carboxyl group in a molecule and fine particles of a metal or metal compound having poor solubility in water. This fiber is then used to make a textile product. This patent application uses metal compounds which are harmful. It does not include essential oil and bioactive components within a biopolymer.

In the patent application WO2015035529A2, antiviral and antimicrobial material fiber is developed that can be used to produce fabrics or sheets. The production of the material with copper filaments is based on the creation of a yarn for producing fabrics with surface that can be kept free of contaminants, such as bacteria, viruses and fungi that are harmful to health, the natural environment. This patent application utilizes fine metallic filaments fused with natural or synthetic fibers by twisting and spinning to make a yarn that can be further used to make fabric. This is not feasible for a daily use material and use of pure metal will make it expensive.

None of these prior art documents discloses the compositions of the present invention as well as the superior advantages of the present invention. Moreover, the present invention provides a simple, cost effective method for preparation of textile coated with the composition which has shown antimicrobial activity even after multiple washes.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a composite composition for sanitizing and disinfecting various surfaces or textiles. Said antimicrobial composition comprises:-

- a biopolymer;

- an essential oil;

- a fatty acid;

- a cross-linking agent; - a surfactant;

- a catalyst; wherein the combination of biopolymer, essential oil and fatty acid forms a bioactive; and wherein the composition is an aqueous composition and essentially free of organic solvents, metallic ions and quaternary ammonium compounds.

In another aspect, the present invention provides method for preparing the afore-mentioned composition of the present invention comprising:- a) dissolving a solution of a biopolymer in a cross-linking agent, a surfactant, a catalyst, and fatty acid present in an aqueous medium to form a mixture; b) heating the mixture solution at 60° to 100°C for 30 to 60 minutes followed by cooling the solution to room temperature; c) adding the essential oil and thoroughly mixing the solution to form the antimicrobial composition.

In yet another aspect, the present invention provides antimicrobial fabrics, textiles or surfaces comprising the afore-mentioned composition.

In yet another aspect, the present invention provides a method of preparing the afore-mentioned fabric comprising: a) dissolving a solution of a biopolymer in a cross-linking agent, a surfactant, a catalyst, and fatty acid present in an aqueous medium to form an emulsion; b) heating the mixture solution at 60° to 100°C for 30 to 60 minutes followed by cooling the solution to room temperature; c) adding the essential oil and thoroughly mixing the solution to form the antimicrobial composition; d) soaking a fabric with the antimicrobial composition of step (c) and heating up to 40°C to 80 °C for 30 minutes to 60 minutes under constant stirring; and e) drying the fabric of step (e) at room temperature for 1 hours to 3 hours. BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description of the invention will be better understood when read in conjunction with the appended drawings. For the purpose of assisting in the explanation of the invention, there are shown in the drawings embodiments which are presently preferred and considered illustrative. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentation shown therein.

Figure 1: Antibacterial activity of the composite material by disk diffusion assay against Staphylococcus aureus

Figure 2: (a) - Coated Personal Protective Equipment (PPE) material with the synthesized composite material;

Figure 3: FITR spectra of (a) coated fabric and (b) coated fabric after 20 wash cycles confirms the retention of active agents

Figure 4: SEM of the composite material

Figure 5: Breathability in comparison to N95

Figure 6: Antimicrobial & Anti-biofilm activity after coating and 20 washes

Figure 7: FTIR of spun bound material

Figure 8: Efficacy of spray based antimicrobial textile

Figure 9: Time kill assay of composite based disinfectant compared with l%hypochlorite Figure 10: Quantitative non-porous surface test for disinfectants Figure 11: Time kill efficiency of the aerosol based disinfectant Figure 12: Skin and Mucosal irritation

Figure 13: Time Kill comparison of sanitizer with 70% alcohol sanitizer Figure 14: Residual kill activity ASTM 3058

Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. DESCRIPTION OF THE INVENTION

For the purposes of the following detailed description, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. Moreover, other than in any operating examples, or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification are to be understood as being modified in all instances by the term "about". It is noted that, unless otherwise stated, all percentages given in this specification and appended claims refer to percentages by weight of the total composition.

Thus, before describing the present invention in detail, it is to be understood that this invention is not limited to particularly exemplified process parameters that may of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments of the invention only, and is not intended to limit the scope of the invention in any manner.

The use of examples anywhere in this specification including examples of any terms discussed herein is illustrative only, and in no way limits the scope and meaning of the invention or of any exemplified term. Likewise, the invention is not limited to various embodiments given in this specification.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the case of conflict, the present document, including definitions will control.

It must be noted that, as used in this specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the content clearly dictates otherwise.

The terms “preferred” and “preferably” refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances.

Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the invention. As used herein, the terms “comprising” “including,” “having,” “containing,” “involving,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to.

As used herein, the term "bioactive agent" refers to any entity (including but not limited to the active ingredient) that has, is intervening or participates in biological activity. In various embodiments, the bioactive agent is formed by the combination of biopolymer, essential oil and fatty acid.

In one aspect, the present invention provides a composite composition which is a nanoemulsion for sanitizing and disinfecting various surfaces or textiles.

The present invention accordingly provides an antimicrobial composition comprising: -

- a biopolymer;

- an essential oil;

- a fatty acid;

- a cross-linking agent;

- a surfactant;

The biopolymer encapsulates essential oil and fatty acid constituents as bioactives making it an effective antiviral material. The said composite composition may also comprise of natural bioactives that have a widespread anti-infective property encompassing antifungal property as well.

The composition of the present invention comprises: a biopolymer; cross-linking agent; surfactant; catalyst; buffer; fatty acid; essential oil such as eugenol; and combinations thereof.

In an embodiment of the present invention, the biopolymer is selected from the group consisting of chitosan, chitosan salt, chitosan derivatives or blends thereof and present in an amount ranging from 0.5-10%w/v. The essential oil is eugenol and is present in an amount ranging from 0.01 - 5.0%w/v.

The fatty acid which may be used in the present invention is oleic acid along with essential oil constituent Eugenol. These components have been incorporated within said biopolymer. In an embodiment of the present invention, the biopolymer, fatty acid such as oleic acid and essential oil such as eugenol forms an emulsion base which is a nanoemulsion. Said the nanoemulsion comprises nanoparticles in the range of 300 nm - 500 nm.

Suitable non-limiting examples of the cross-linking agent are acetic acid, citric acid, maleic acid, 1, 2, 3, 4-butanetetracarboxylic acid (BTC A). The cross-linking agent is present in an amount ranging from 0.2-10% w/v.

Suitable non-limiting examples of the surfactant are Tween 80, Tween 20, span 20 and span 80. The surfactant is present in an amount ranging from 0.01 - 3% w/v.

Suitable non-limiting examples of the catalyst are sodium dihydrogen phosphate, ammonium dihydrogen phosphate, potassium dihydrogen phosphate, di-potassium hydrogen phosphate. The catalyst is present in an amount ranging from 0.01-5% w/v.

The buffer in the buffer system includes phosphate buffer and present in an amount ranging from 0.5 - 3.5 % w/v. The fatty acid is oleic acid and present in an amount ranging from 0.01 - 5.0%w/v.

In an embodiment of the present invention, the composition optionally comprising a humectant selected from the group consisting of glycerine or glycerol and present in an amount ranging from 1 to 10%w/v.

In yet another aspect, the present invention provides antimicrobial textiles/surfaces comprising the afore-mentioned composition.

The present invention provides a fabric comprising the antimicrobial composition as claimed in claim 1, wherein the antimicrobial composition is coated onto the fabric.

Said fabric may be selected from the group consisting of natural fibers, synthetic cellulosic fibers, regenerated protein fibers, acrylic fibers, polyolefin fibers, polyurethane fibers, vinyl fibers, cotton, nylon, rayon, polyamide fibers, spunbound polypropylene and blends thereof.

The present invention also provides a method of preparing the afore -mentioned fabric comprising: a) dissolving a solution of a biopolymer in a cross-linking agent, a surfactant, a catalyst, and fatty acid present in an aqueous medium to form an emulsion; b) heating the mixture solution at 60° to 100°C for 30 to 60 minutes followed by cooling the solution to room temperature; c) adding the essential oil and thoroughly mixing the solution to form the antimicrobial composition; d) soaking a fabric with the antimicrobial composition of step (c) and heating up to 40°C to 80 °C for 30 minutes to 60 minutes under constant stirring; and e) drying the fabric of step (e) at room temperature for 1 hours to 3 hours.

The present invention also provides a textile product comprising the afore-mentioned fabric. The textile product may be selected from cloth mask, face mask, woven fabric, non-woven fabric, apparel, apparel interlining, upholstery, carpeting, padding, backing, wall coverings, curtains, roofing products, house wraps, insulation, bedding, wiping cloths, towels, gloves, socks, rugs, floor mats, drapery, napery, bar runners, textile bags, barrier clothing, filters in respirators, air purifiers, air cons, other air flow systems, leather based product, awnings, vehicle covers, boat covers, tents, agricultural coverings, geotextiles, automotive headliners, filters, envelopes, tags, labels, diapers, facing sheets for sanitary products, feminine hygiene products, laundry aids, wound care products, antibacterial wipes, medical robes, medical bandages, medical sheets and medical care products.

In yet another aspect, the present invention provides methods for treating textiles or surfaces with said composition for sanitization and disinfection.

In yet another aspect, the antimicrobial composition may be used in an industrial or a consumer application selected from the group consisting of hand sanitizer, body sanitizer, aerosol disinfection, surface disinfection, enclosed area spray, fumigation, disinfection tunnel, fabric spray and textile spray.

The present invention provides a composite material/composition with broad spectrum antimicrobial (inclusive of antibacterial, antifungal & antiviral) property to be used as a coating material for fabric/ textile and as an aerosol disinfectant. The said composition comprises of a biopolymeric base that makes it antimicrobial, effective against both Gram positive and Gram Negative bacteria and viruses. This composite composition may be placed in different polymeric base’s to ensure dip coat, spray coat and layer coat properties. The coatings on textile materials and fabrics have been confirmed by spectral studies (Figure 3) identifying the functional groups and confirming the presence of active agents on the fabric after few wash cycles. Thus making fabrics with such coating will be usable in critical care and intensive care for healthcare professionals and others to avoid transmission of various pathogens that lead to infections. Alternately the composite material/composition can be diluted to an aqueous mixture with easy to flow and spray property, to be used as an aerosol disinfectant in various zones for reducing the rate of transmission and ensuring good hygiene.

The said composite material is proven antibacterial as confirmed by disk diffusion method against Staphylococcus aureus and Klebsiella pneumoniae. Also the composite material is found to non-toxic and non-irritant to skin. The added antiviral and bioactive components enhance the spectrum of the composite to encompass antiviral and antifungal property as well. Further the composite has been cross-linked to fabric material by treating the fabric with the composite at slightly higher temperature up to 80° C and mixed for not more than 1 hour. This fabric material is confirmed to retain the anti-infective property of the composite and thus usable by multiple textile units like clothing, sportswear, personal protective equipment (PPE) material for healthcare and linen with activity retained for 20 - 40 wash cycles The compositions of the present invention may also be used to produce wipes/tissue paper, such as ready-to-use wipes.

The unique composition of the nanoemulsion with the bioactive at requisite concentration enables surfactant like property of the composite arising from the synergistic action of its ingredients and their chemical interactions with added catalyst and buffer systems makes it a strong antimicrobial material. The underlying mechanism being the complete degradation of the viral envelope and at least partial breakdown of the capsid. The loss of the envelope containing the viral proteins involved in virus adsorption and penetration accounts for the loss of virus infectivity. In case of bacteria, emulsion causes rapid degradation of the bacterial cell wall of both Gram Positive and Gram negative bacteria. . The invented emulsion composites can be used for prevention of virus, bacterial and fungal transmissions.

Alternately the composite material/composition is also found to retain its anti-infective property against bacterial, fungal and viral pathogens in a diluted aqueous medium. The composite composition of the present invention is surface active and can be aerosolized into droplets through a pressurized pump based instrument and based on the nozzle used size of the droplet is controlled to 25-50 micron that is ideal for aerosol/ spray of disinfectant to ensure droplets land to the surface and retention on the landed surface depends on the properties of the material. This makes it into a convenient spray able form usable as an aerosol disinfectant across multiple surfaces/ utilities to ensure hygienic surroundings indoor as well as outdoors, walk through chambers, confined areas and multi-storey constructions. Other suitable examples of surfaces include, without limitation, where the aerosol disinfectant may be applied are food contact surfaces (e.g., eating utensils, sinks, stovetops, countertops, table-tops, and cutting boards), children's toys, surfaces associated with day cares and nurseries (e.g., cribs, high chairs, etc.), lavatory fixtures and appliances (e.g., toilets, shower stalls, bathtubs, and bathing appliances), wall and flooring surfaces, surfaces associated with hospital environments, medical laboratories, and medical treatment environments (e.g., laboratory glass ware, medical testing equipment, and bedpans).

The following examples are provided to better illustrate the present invention and are not to be interpreted in any way as limiting the scope of the invention. All specific materials and methods described below, in whole or in part, fall within the scope of the invention. These specific compositions, materials, and methods are not intended to limit the invention, but merely to illustrate specific embodiments falling within the scope of the invention. One skilled in the art may develop equivalent materials, and methods without the exercise of inventive capacity and without departing from the scope of the invention. It will be understood that many variations can be made in the procedures herein described while still remaining within the bounds of the invention. It is the intention of the inventors that such variations are included within the scope of the invention.

EXAMPLES:

One of the exemplary composition of the present invention comprises biopolymer like chitosan, chitosan salt or chitosan derivatives may be used in the range of 0.5-10%w/v dissolved in an acidic medium using any of the acids ranging from Acetic acid to Citric acid (0-5%w/v), surfactant like tween-80 (0.01 - 1.0%w/v), a catalyst and a buffer system developed using phosphate buffer (0.5 - 3.5 %w/v) and naturally occurring fatty acid like Oleic acid (0.01 - 1.0%w/v). A mixture of all these compounds in aqueous medium heated up to 60° - 100°C for 30-60 minutes. Followed by cooling the solution to room temperature and addition of eugenol (99% purity) (0.01 - 1.0%w/v) and thoroughly mixed. The composite thus obtained is usable. Tween 80 in the range of 0.05-0.2%w/v may be used as surfactant. Other surfactants like tween 20 (0.1-3% w/v), span 20 (0.1-3% w/v), span 80 (0.1-3% w/v), Quaternary ammonium salts or any non-anionic surfactants may also be used. Non formaldehyde cross-linking agents like maleic acid (0.2-10% w/v) and 1, 2, 3, 4-butanetetracarboxylic acid (BTCA) (0.2-5% w/v) can be used instead of citric acid. Sodium dihydrogen phosphate in the range of 0.01-0.5%w/v is used as catalyst for the reaction. Ammonium dihydrogen phosphate (0.5-5%w/v), Potassium dihydrogen phosphate (0.5-5% w/v), di-potassium hydrogen phosphate (0.5-5% w/v), may also be used as catalyst. Oleic acid and essential oil constituent Eugenol have been incorporated within the biopolymer and lead to a synergistic antiviral activity.

The composite nanoemulsion/composition is shown to have antibacterial activity by the well diffusion method [Figure 1] The coating of composition on the fabric/textile is confirmed by Figure 2 which shows the coated textile masks. Figure 3 shows the characteristic peaks of the coating material on FTIR analysis. Figure 4 shows the formation of a nanoemulsion. The composite emulsion showed presence of nanoparticles (nano-sized droplets) in the range of 300 nm - 500 nm as seen in the SEM [Figure 4].

Example 2: Antimicrobial textile/fabric

The said invention can be used for developing antimicrobial textile material. Depending on the method of application on the fabric the antimicrobial efficiency can be obtained for long duration until 20 washes or only for single use i.e. one wash.

For specific applications like use in healthcare the composite material (concentration at least 10000 ppm of the biopolymer) is coated onto the fabric following coating procedure that helps attach the actives in the composite to cross-link with the fibers and provide long term protection for 20 to 40 washes [Figure 3a after coating and 3b after 20 washes]. The coating procedure involves soaking the fabric in composite material for 30 - 60 minutes at temperature of 40 - 80° C under constant stirring. The fabric retains the antimicrobial activity and without affecting breathability a critical factor for use of mask in healthcare [Figure 5]. The said coating procedure is applicable to all healthcare products including face mask [Figure 2], PPE, coveralls, Bed linen and gloves made of woven fabric like cotton, rayon, polyester viscose and others.

In other ways the composite material (concentration at least 7000 ppm of the biopolymer) can be used as a spray for apparels and other porous surfaces for short term protection that lasts for at least 24 hours or until first wash after the spray. The spray method involves spraying the material over the apparel or wearable textile for instant use and protection through the day. The spray can be used over range of textile made of cotton, polyester viscose and all types of woven fabrics.

Example 5: Surface disinfection for non - porous surface

The composite material (concentration at least 5000 ppm of the biopolymer) can be used as a surface disinfectant on various non - porous surfaces like glass, plastic, metal surfaces, vitrified flooring, sanitary ware, automobiles and other high touch surfaces. The composite provides instant antimicrobial protection and is retained for at least more than 24 hrs. The composite can be sprayed, poured or wiped on the surface using suitable container. The efficiency of the composite material is compared to commonly used surface disinfectants.

Example 6: Aerosol disinfection / Room spray / Fumigation / Disinfection tunnel

In yet another application the composite material (concentration at least 7000 ppm of the biopolymer) can be used as an aerosol based disinfectant for enclosed areas like, rooms, halls, classrooms, cars, aircrafts, cabins, cabinets. The spray form of the composite releases aerosols from actuator based pumps, spray cans, fogging and fumigation apparatus. The aerosols are suspended in air and provide immediate antimicrobial activity against bacteria, fungi and virus particles suspended in air. The natural ingredients and non-toxic nature of the material allows long term usage and does not have any harmful effects on skin and mucosal sites. The efficiency of the composite material is compared to commonly used aerosol disinfectants.

Example 7: Hand & Body sanitizer

Another application of composite material is its use as a hand & body sanitizer. The composite material (concentration at least 5000 ppm of the biopolymer) along with a humectant component like glycerine or glycerol acts as an excellent sanitizing solution along with enhanced moisture retention in skin which is not observed in commonly used alcohol based sanitizers. The efficiency and residual effect of the composite based sanitizer is found to be equivalent to 70 % alcohol based sanitizer.

Results and Description of figures: 1) Antimicrobial activity - The composite emulsion was shown to have antibacterial activity by the well diffusion method [Figure 1]

2) Proof of coating on textiles - Figure 2 shows the coated textile masks. Figure 3 shows the characteristic peaks of the coating material on FTIR analysis.

3) Formation of a nanoemulsion - The composite emulsion showed presence of nanosized droplets in the range of 300 - 500 nm as seen in the SEM [Figure 4].

4) Breathability of nanoemulsion/composition coated textile mask in comparison to N95

The composite coated mask was evaluated for its breathability an essential parameter for qualification as per ASTM & ISO standards. The breathability is determined by the differential pressure caused by the resistance to flow of air through the mask. The lower the resistance the better is the breathability of the mask. N95 mask are considered to be the most effective in controlling the transmission of infections but are often low on comfort and breathability is just below the standard acceptance of 40 PaCm². On the other hand the composite coated mask was found to have the least resistance indicating most comfortable breathing along with extended protection against bacterial and viral pathogens [Figure 5].

5) Antimicrobial & Anti-biofilm activity after coating textiles with the nanoemulsion/composition and after 20 washes of the coated textile

To determine the antimicrobial efficacy of the composite coated fabric various antimicrobial assays for textile samples were done. The Standard AATCC 147 to qualitatively determine the antimicrobial activity of functionalized textile showing clear margins and zone of inhibition around the coated fabric and coated + washed (20 times) as against an overgrown bacterial culture over the uncoated fabric. The quantitative estimation by AATCC 100 method for three different pathogens showed more than 4 log reduction in the number as against uncoated fabric. The microscopic examination of bacteria challenged fabric shows numerous bacteria over the uncoated (control) and almost none in the coated fabric. The determination of anti -biofilm activity of functionalized textile is much important especially in cases where the said textile is used in high infection or contamination zones like face mask and PPE for healthcare. The anti biofilm activity determined using the confocal analysis of coated fabric challenged with three different pathogens reveals total reduction or complete inactivation of the microbes on the coated fabric as compared to uncoated (control) [Figure 6] .

6) Proof of coating of nanoemulsion/composition on spun bound material

Apart from the coating the textile material like woven fabric, the composite was also used to coat other non-woven materials like spun bound polypropylene, filter glass material and leather products. The composite material comprises of actives live chitosan and eugenols, upon successful coating on a product the typical amine groups are observed in the FTIR spectra of the coated sample. Thus FTIR analysis becomes the preliminary test to confirm the presence of coating. The differential regions of 3500, 1600 and 1700 in a coated sample as against uncoated confirm the presence of coating. The FTIR spectra in the drawing confirm the presence of coating in spun bound polypropylene non-woven material commonly used as filter material [Figure 7]. 7) Efficacy of spray based emulsion/composition for antimicrobial textile

The composite material can also be used as a spray for apparels and linens to acquire short term protection i.e. minimum 24 hours or till first wash after spray. A complete protection against bacterial and viral pathogens is achieved by spraying the composite across the apparel. To determine the antimicrobial efficacy of the spray format, fabric of cotton material was used and sprayed with the composite using an actuator based spray bottle. The coated fabric was then challenged with pathogens at various times point starting from 10 second to 24 hours to evaluate the antimicrobial efficiency. The results for the same indicated almost 99.9% activity within 10 second and retained 100 % activity for at least 24 hours [Figure 8].

8) Time kill assay of composite based disinfectant compared with l%hypochlorite

An effective surface disinfectant is classified by it maximum killing efficiency for all types of microbes in the lowest time point. Thus standard time kill estimation by ASTM E2315 is determined using various bacterial, fungal and viral pathogens. In order to evaluate the efficacy of the composite based disinfectant the time kill assay was performed in comparison to 1% hypochlorite commonly used and recommended surface disinfectant by the WHO. The results of the analysis revealed equivalent efficacy of composite based surface disinfectant to 1% hypochlorite against all the pathogens even in the lowest time point of 10 seconds [Figure 9].

9) Quantitative non-porous surface test for the disinfectant property of the nanoemulsion/composition

A surface disinfectant requires its efficacy to be maintained over long period of time, to determine the same standard evaluation method like EN 13697 are performed. The Quantitative estimation of microbial reduction over various time points upon challenge with pathogens on a non-porous surface disinfectant using the test material is done. The log reduction is as compared to the initial concentration is expected to be maintained over all the time points of the study. The results of the study with composite material used as surface disinfectant on a non-porous surface like glass and steel indicate constant reduction of microbes maintained through all the time points. The results confirm the long term efficacy at least 24 hours of the composite based surface disinfectant. The results also imply the single use of the composite disinfectant giving protection for 24 hrs and no requirement of regular application every 6 - 8 hrs like other disinfectants [Figure 10]. 10) Time kill efficiency of the nanoemulsion/composition in the form of an aerosol based disinfectant

An aerosol disinfectant is required to have maximum killing efficiency for all types of microbes in the lowest time point and in its suspension form. Thus standard time kill estimation by ASTM E2315 is determined using various bacterial, fungal and viral pathogens. In order to evaluate the efficacy of the composite based disinfectant the time kill assay was performed. The results reveal 99.9% efficacy within 10 seconds for all types of pathogens including bacterial, fungal and viral particles. The calculated time of the composite material in aerosolized form that remains in areal suspension is 1.5 times more than its lowest kill time. This qualifies the composite material to be recognized as an aerosol based disinfectant to be used for sanitization through spray or fogging / fumigation of enclosed areas like rooms, offices and cars [Figure 11].

11) Non -irritant nature of nanoemulsion/composition based on Skin and Mucosal irritation tests in small animals

Use of aerosolized disinfectants is often discouraged due to toxicity and irritation issues pertaining to the use of hazardous chemicals. In order to confirm the composite based disinfectant is non-irritant to both skin and mucosal tissues, preliminarily exposed regions to aerosolized materials, animal studies as per OECD guideline were undertaken. Skin irritation in rabbits and mucosal irritation in hamsters was compared to a non-irritant control like saline (0.9% NaCl) and irritant material like SDS. The composite (coded - NE) was found to completely non-irritant with no signs of erythema or edema. Also the scoring of the composite material in both cases was equivalent to non-irritant control sample. The animals were reported to be healthy at the end of study with irritation index scored “0” in both animals for skin and mucosal irritation respectively [Figure 12].

12) Time Kill comparison of the nanoemulsion/composition as a sanitizer with 70% alcohol sanitizer

WHO recommends 70% alcohol as an effective hand sanitizer mainly due to its maximum killing efficiency for all types of microbes in the lowest time point. Thus standard time kill estimation by ASTM E2315 is determined using various bacterial, fungal and viral pathogens. In order to evaluate the efficacy of the composite based hand and body sanitizer the time kill assay was performed in comparison to 70% alcohol sanitizer commonly used. The results of the analysis revealed equivalent efficacy of composite based sanitizer to 70% alcohol sanitizer against all the pathogens even in the lowest time point of 10 seconds. Additionally the composite material was evaluated for its anti SARS-CoV2 activity by the RT PCR method for a time point of 60 mins using COVID - 19 positive patients’ samples. The reduction of virus confirmed its efficiency against the SARS-CoV2 virus. The broad spectrum activity of the composite material against Gram positive & Gram negative bacteria, yeast & mold fungi, enveloped & non-enveloped viruses makes it a reliable material to neutralize all pathogens on skin surface and control transmission [Figure 13].

13) Residual kill activity in accordance with ASTM 3058

Use of hand sanitizer is based on incidence of touch on contaminated or suspected infection harbouring fomites or individuals. But an effective model analysis to reveal the extent of activity retained until next touch is evaluated by residual kill activity standard procedure ASTM 3058. The test is based on actual application of sanitizer and challenge with bacterial pathogen over period of time to determine its residual kill efficiency over the time points. The composite based sanitizer was equally effective with more than 99.9 % to alcohol based sanitizer for a period of two hours. The retention of killing efficiency for a long period like two hours makes the composite material based hand and body sanitizer a relevant substitute with its preferred biocompatibility, biodegradability and non-irritant benefits [Figure 14].

Claims

CLAIMS:

1) An antimicrobial composition comprising:-

- a biopolymer;

- an essential oil;

- a fatty acid;

- a cross-linking agent;

- a surfactant;

2) The antimicrobial composition as claimed in claim 1, wherein the biopolymer is chitosan, chitosan salt or chitosan derivatives and present in an amount ranging from 0.5-10%w/v.

3) The antimicrobial composition as claimed in claim 1, wherein the essential oil is eugenol and present in an amount ranging from 0.01 - 5.0%w/v.

4) The antimicrobial composition as claimed in claim 1, wherein the fatty acid is oleic acid and present in an amount ranging from 0.01 - 5.0%w/v.

5) The antimicrobial composition as claimed in claim 1, wherein the cross-linking agent is selected from the group consisting of acetic acid, citric acid, maleic acid, 1, 2, 3, 4- butanetetracarboxylic acid (BTCA) and present in an amount ranging from 0.2-10% w/v.

6) The antimicrobial composition as claimed in claim 1, wherein the surfactant is selected from the group consisting of Tween 80, Tween 20, span 20 and span 80 and present in an amount ranging from 0.01 - 3% w/v.

7) The antimicrobial composition as claimed in claim 1, wherein the catalyst is sodium dihydrogen phosphate, ammonium dihydrogen phosphate, potassium dihydrogen phosphate, di-potassium hydrogen phosphate and present in an amount ranging from 0.01-5% w/v. 8) The antimicrobial composition as claimed in claim 1, wherein the biopolymer, fatty acid and essential oil forms an emulsion base which is a nanoemulsion.

9) The antimicrobial composition as claimed in claim 8, wherein the nanoemulsion comprises nanoparticles in the range of 300 nm - 500 nm.

10) The antimicrobial composition as claimed in claim 1, optionally comprising a humectant selected from the group consisting of glycerine or glycerol and present in an amount ranging from 1 to lOw/v.

11) The antimicrobial composition as claimed in claim 1, for use in an industrial or a consumer application selected from the group consisting of hand sanitizer, body sanitizer, aerosol disinfection, surface disinfection, enclosed area spray, fumigation, disinfection tunnel, fabric spray and textile spray.

12) A fabric comprising the antimicrobial composition as claimed in claim 1, wherein the antimicrobial composition is coated onto the fabric.

13) The fabric as claimed in claim 12, wherein the fabric is selected from the group consisting of natural fibers, synthetic cellulosic fibers, regenerated protein fibers, acrylic fibers, polyolefin fibers, polyurethane fibers, vinyl fibers, cotton, nylon, rayon, polyamide fibers, spunbound polypropylene and blends thereof.

14) A textile product comprising the fabric as claimed in claim 12, wherein the textile product is selected from cloth mask, face mask, woven fabric, non-woven fabric, apparel, apparel interlining, upholstery, carpeting, padding, backing, wall coverings, curtains, roofing products, house wraps, insulation, bedding, wiping cloths, towels, gloves, socks, rugs, floor mats, drapery, napery, bar runners, textile bags, barrier clothing, filters in respirators, air purifiers, air cons, other air flow systems, leather based product, awnings, vehicle covers, boat covers, tents, agricultural coverings, geotextiles, automotive headliners, filters, envelopes, tags, labels, diapers, facing sheets for sanitary products, feminine hygiene products, laundry aids, wound care products, antibacterial wipes, medical robes, medical bandages, medical sheets and medical care products. 15) A method of preparing the antimicrobial composition as claimed in claim 1, comprising: a) dissolving a solution of a biopolymer in a cross-linking agent, a surfactant, a catalyst, and fatty acid present in an aqueous medium to form a mixture; b) heating the mixture solution at 60° to 100°C for 30 to 60 minutes followed by cooling the solution to room temperature; c) adding the essential oil and thoroughly mixing the solution to form the antimicrobial composition.

16) A method of preparing a fabric as claimed in claim 12, comprising: a) dissolving a solution of a biopolymer in a cross-linking agent, a surfactant, a catalyst, and fatty acid present in an aqueous medium to form an emulsion; b) heating the mixture solution at 60° to 100°C for 30 to 60 minutes followed by cooling the solution to room temperature; c) adding the essential oil and thoroughly mixing the solution to form the antimicrobial composition; d) soaking a fabric with the antimicrobial composition of step (c) and heating up to 40°C to 80 °C for 30 minutes to 60 minutes under constant stirring; and e) drying the fabric of step (e) at room temperature for 1 hours to 3 hours.